1. Technical Field
The invention relates to 6-aminouracils, substituted in position 5, which are of the formula I depicted below and are intended for stabilizing chlorine-containing polymers, especially PVC.
2. Prior Art
PVC can be stabilized by a range of additives. Compounds of lead, of barium and of cadmium are particularly suitable for this purpose but are nowadays controversial on ecological grounds or because of their heavy metal content (cf. "Kunststoffadditive", R. Gachter/H. Muller, Carl Hanser Verlag, 3rd ed., 1989, pages 303-311, and "Kunststoff Handbuch PVC", volume 2/1, W. Becker/D. Braun, Carl Hanser Verlag, 2nd ed., 1985, pages 531-538; and also Kirk-Othmer: "Encyclopedia of Chemical Technology", 4.sup.th ed., 1994, Vol. 12, Heat Stabilizers, pp. 1071-1091). The search therefore continues for effective stabilizers and stabilizer combinations which are free from lead, barium and cadmium.
1,3-disubstituted aminouracils have already been described in U.S. Pat. No. 3,436,362, U.S. Pat. No. 4,656,209, U.S. Pat. No. 4,352,903 and EP-A-0 768 336 and can be prepared by known methods in one (or more) process steps.